1. Field of the Invention
The present invention relates to a developing cartridge, a process cartridge, and an image forming device.
2. Description of Related Art
A process cartridge is detachably mounted in a conventional image forming device such as a laser printer. A developing cartridge is detachably mounted in the process cartridge. The developing cartridge has a housing in which toner is accommodated. The housing of the developing cartridge is formed with an opening. A developing roller is rotatably supported in the housing at the opening.
When the developing cartridge is mounted on the process cartridge, the developing roller is placed in confrontation with a photosensitive drum in the process cartridge. By rotating the developing roller while in confrontation with the photosensitive drum, an electrostatic latent image formed on the photosensitive drum is developed into a visual toner image. By transferring the toner image onto a sheet of paper, it is possible to form a desired image on the sheet of paper.
The developing cartridge further includes side seals for preventing toner carried on the developing roller from leaking outside from the housing of the developing cartridge. The side seals are disposed at both ends of the developing roller with respect to its axial direction so as to make sliding contact with a circumferential surface of the developing roller at the both ends.
U.S. Pat. No. 6,356,723 and U.S. patent application Publication No. 2003/118364 have proposed a configuration in which the side seal includes: a sponge seal that is formed of urethane sponge and that is affixed to the housing: and a sliding sealing element that is formed of felt or a woven fabric and that is affixed to the upper surface of the sponge seal.